title: Two plus blue equals green: grapheme-color synesthesia allows cognitive access to numerical information via color.
abstract: In grapheme-color synesthesia, graphemes (e.g., numbers or letters) evoke color experiences. It is generally reported that the opposite is not true: colors will not generate experiences of graphemes or their associated information. However, recent research has provided evidence that colors can implicitly elicit symbolic representations of associated graphemes. Here, we examine if these representations can be cognitively accessed. Using a mathematical verification task replacing graphemes with color patches, we find that synesthetes can verify such problems with colors as accurately as with graphemes. Doing so, however, takes time: ~250 ms per color. Moreover, we find minimal reaction time switch-costs for switching between computing with graphemes and colors. This demonstrates that given specific task demands, synesthetes can cognitively access numerical information elicited by physical colors, and they do so as accurately as with graphemes. We discuss these results in the context of possible cognitive strategies used to access the information.
authors.affiliation: Department of Psychology, University of Nevada, Mail Stop 296, Reno, NV 89557, USA. Electronic address: mcdan27@gmail.com.
authors.forename: J Daniel
authors.initials: JD
authors.lastname: McCarthy
authors.forename: Lianne N
authors.initials: LN
authors.lastname: Barnes
authors.forename: Bryan D
authors.initials: BD
authors.lastname: Alvarez
authors.forename: Gideon Paul
authors.initials: GP
authors.lastname: Caplovitz
mesh_terms: D001244:Association; D003071:Cognition / Q000502:physiology*; D003118:Color Perception / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D010468:Perceptual Disorders / Q000503:physiopathology*; D011930:Reaction Time; D000080311:Synesthesia; D055815:Young Adult
keywords: Bidirectionality; Mental arithmetic; Numerical cognition; Synesthesia